(1) Field of the Invention
The invention relates to a phosphorus compound useful as a ligand of a metal catalyst and a production process thereof.
(2) Description of the Related Art
Conventionally, many reports have been published on transition metal complexes usable as a catalyst for an asymmetric reaction such as asymmetric hydrogenation reaction, asymmetric isomerization reaction, and asymmetric hydrosilylation reaction. Especially, complexes containing a transition metal such as ruthenium, rhodium, iridium, palladium, or the like and an optically active phosphine compound coordinated with the metal have widely been known as a high performance catalyst for an asymmetric synthesis reaction. Among such optically active phosphine compounds, an optically active biaryl phosphine compound with axial asymmetry is useful as an optically active ligand of an asymmetric reaction catalyst (see, for example, Tetrahedron, 2005, Vol. 61, 5405-5432). Many of the processes to synthesize such an optically active biaryl compound involve homo- or cross-coupling of two aryl units, and require optical resolution to obtain an optically active substance after the coupling (see, for example, JP-A-2000-16997 and JP-A-10-182678). To synthesize an optically active biaryl phosphine compound, it is required to introduce a phosphorus atom site into the biaryl skeleton before or after the synthesis of the biaryl compound by the above-mentioned homo- or cross-coupling (see, for example, JP-A-10-182678 and JP-T-10-501234). On the other hand, recently, as a new technique for synthesizing an optically active biaryl compound, a technique involving enantio-selective [2+2+2] cycloaddition reaction using alkynes has also been developed (Organic Letters, 2006, Vol. 8, 3489-3492).